From: Rosen Penev <rosenp@gmail.com>
To: Bartosz Golaszewski <brgl@kernel.org>
Cc: Kees Cook <kees@kernel.org>,
linux-gpio@vger.kernel.org,
Bamvor Jian Zhang <bamv2005@gmail.com>,
Linus Walleij <linusw@kernel.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:KERNEL HARDENING (not covered by other
areas):Keyword:b__counted_by(_le|_be)?b"
<linux-hardening@vger.kernel.org>
Subject: Re: [PATCH] gpio: mockup: allocate lines with main struct
Date: Mon, 23 Mar 2026 09:43:00 -0700 [thread overview]
Message-ID: <CAKxU2N9KdziPen9-_gfe0UZjyuMTOsbb583aeF3=kqm22rGieA@mail.gmail.com> (raw)
In-Reply-To: <CAMRc=MctGTeqBHQ8zaQ7_2YAoWoTUxOK4_hs+-EHEQEPnz+A-g@mail.gmail.com>
On Mon, Mar 23, 2026 at 3:00 AM Bartosz Golaszewski <brgl@kernel.org> wrote:
>
> On Sat, Mar 21, 2026 at 12:00 AM Rosen Penev <rosenp@gmail.com> wrote:
> >
> > >
> > > static int gpio_mockup_probe(struct platform_device *pdev)
> > > {
> > > ...
> > > u16 ngpio;
> > > ...
> > > rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
> > > ...
> > > gc->ngpio = ngpio;
> > > ...
> > > chip->lines = devm_kcalloc(dev, gc->ngpio,
> > > sizeof(*chip->lines), GFP_KERNEL);
> > >
> > > But this begs the question: why add nr_lines when ngpio is already part
> > > of the struct:
> > Maintainers for some inexplicable reason want an extra variable for
> > __counted_by works.
>
> I believe what Kees means here is: you can use ngpio for __counted_by() like so:
>
> __counted_by(gc.ngpio)
__counted_by doesn't support nested variables like that.
drivers/gpio/gpio-mockup.c:59:61: error: ‘gc’ undeclared here (not in
a function)
59 | struct gpio_mockup_line_status lines[] __counted_by(gc.ngpio);
>
> I didn't think about it and I do prefer it of course over an extra field.
>
> Bart
next prev parent reply other threads:[~2026-03-23 16:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-19 0:05 [PATCH] gpio: mockup: allocate lines with main struct Rosen Penev
2026-03-20 13:28 ` Linus Walleij
2026-03-20 18:10 ` Kees Cook
2026-03-20 23:00 ` Rosen Penev
2026-03-23 10:00 ` Bartosz Golaszewski
2026-03-23 16:43 ` Rosen Penev [this message]
2026-03-24 9:16 ` Bartosz Golaszewski
2026-03-24 15:51 ` Rosen Penev
2026-03-24 15:54 ` Bartosz Golaszewski
2026-03-24 15:56 ` Rosen Penev
2026-03-24 17:16 ` Bartosz Golaszewski
2026-03-24 18:25 ` Rosen Penev
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